Process and apparatus for the continuous extraction or treatment of liquids



April 7, 1936. h C CQUTOR 2,036,924-

PROCESS AND APPARATUS FOR THE CONTINUOUS EXTRACTION OR TREATMENT OFLIQUIDS Filed May 14, 1934 2 Sheets-Sheet l By: 777% ZZ/A April 7, 1936.Q CQUTQR 2,036,924

PROCESS AND APPARATUS FOR THE CONTINUOUS EXTRACTION OR TREATMENT OFLIQUIDS Filed May 14, 1934 2 Sheets-Sheet 2 Patented Apr. 7, 1936 PATENTOFFICE PROCESS AND APPARATUS FOR THE CON- TINUOUS EXTRACTION ORTREATMENT OF LIQUIDS Charles Coutor, Premery, France, assignor to SocitEtablissements Lambiotte Freres, Premery (Nievre Department), FranceApplication May 14, 1934, Serial No. 725,630 In France May 19, 1933 7Claims.

It is a common practice in industry to extract a definite body from amixture constituting a liquid phase by a solvent or a reagent alsoliquid and non-miscible with the mixture under consideration. I

For that purpose, use is generally made of columns of thecounter-current type, with or without an inner lining, or a series ofmixers provided with mechanical stirrers, followed by dem cantingapparatus; according to certain processes, the totality or a portion ofthe vapours of the solvent is used, in columns, for mixing or moving theliquids.

All these apparatus used have the inconvenience of being either ofinsuflicient efficiency, or difficult to carry into practice, and arecostly.

The present invention has for its object a process allowing tocontinuously effect, by a single passage through a simple and compactapparatus, the methodical and complete extraction or treatment of aliquid by another liquid acting as solvent or reagent.

The process according to the invention is mainly characterized by thefact that the circulation and separation of the various products:

mixture to be treated, solvent or reagent, intermediate and finalproducts, are automatically ensured by centrifugal force, which is used,for that purpose, in the following conditions:

(a) The liquids are caused to circulate on the counter-currentprinciple, eventually in a multistage apparatus, for ensuring amethodical and complete exhaustion of the mixture.

(b) Both liquids (solvent or reagent and mixture) are simultaneouslycaused to enter through fixed pipes, and they are simultaneouslyprojected on conical walls rotating at a high speed. (c) Eventually, useis made, concurrently with the movable walls, of fixed surfaces arrangedvery near the latter, so as to produce, by friction, a thorough stirringand intimate mixing of the liquids; this result can also be obtained byatomization, for instance under the action of the available pressure ofthe liquids.

(d) The centrifugal force produces the sepa-- ration of the emulsifiedmixture into concentric layers of different densities, viz.: into alayer comprising the solvent or reagent loaded with the body to beextracted, and into another layer 50 formed by the impoverished mixture.

(e) The bodies forming these various layers are separately drawn off byscoop-pipes similar to those of centrifugal apparatus of the so-calledcream separator type, these scoop pipes con- 55 veying the variousproducts as stated, that is to REISSUED say on the counter-currentprinciple and through several stages in which the above operations arerepeated.

When these operations are terminated, the solvent or reagent and thebody it has carried along 5 are separated by any suitable process, forinstance by distillation, or again by a treatment according to a processsimilar to that indicated above.

Of course,'for carrying out the process the principle of which has justbeen set forth, it is possible to provide any suitable arrangements,capable of varying in the widest limits, according to the conditions ofapplication (nature 01' the products to be treated, of the operations tobe effected, etc.) without departing thereby from the scope of theinvention.

The number and variety of the possible applications of this process arein fact very extensive: for instance, and without this enumerationsbeing in any way limitative, can be cited: the removal of tar frompyrolignous acids, removal of oil from methyl phlegms, purification ofresidual waters, extraction of acetic acid from its aqueous solutions,extraction of acetic acid from tars by washing with water, extraction ofethyl and methyl alcohols from their mixtures with ethers, separation ofthe anhydride-acetic acid mixture by petroleum, extraction of phenols,extraction of essential oils, acid or alkali treatments of petroleum onthe counter-current principle, purification of oils and greases byoxidation or reduction, etc.

Likewise, any suitable plant can be devised for carrying this processinto practice and especially any suitable modifications, considering theparticular conditions of application, can be made in the dimensions ofthe apparatus, arrangement of the scoop-pipes, number of stages-or oisuccessive treatments, etc.

In certain cases it may be desirable or possible, considering thecomplexity of the mixture, to discern more than two concentric layerscapable of being simultaneously separated; additional scoop-pipes andpartitions can then be provided and suitably arranged.

Concerning that point, one may be led to draw off, in the form ofsludge, a precipitate the density of which will be comprised betweenthose of both liquids.

Likewise, one may be led to use as reagent a pulverulent productpractically behaving as a liquid in the various partitions of theapparatus, but, in this case, the scoop-pipes and mixing devices will ofcourse be modified. This will be done every time a liquid will betreated by a carbon or discolouring earth for instance.

Furthermore, use can be made, without departing from the invention, of.a centrifugal apparatus rotating about an axis of orientation, theliquids can be introduced in said apparatus after previous cooling orreheating, and, consequently, the apparatus can be heat insulated orheated, the operation can be effected in presence of any gas, undervacuum or under pressure, etc.

By way of example, and in order that the invention may be more clearlyunderstood, a form of construction of such an apparatus will bedescribed hereinafter with reference to the accompanying drawings, thisapparatus being adapted to be used for the extraction of a bodydissolved in water, by means of a light solvent.

Figure 1 is an axial vertical section of the entire apparatus.

Fig. 1 is a cross section made according to broken line V-V of Fig. 1.

Fig. 1 is a partial section, on an enlarged scale, made according toline 2-2 of Fig. 1

Figure 2 is a similar partial view of a modificacation.

This apparatus comprises a turbine body I, capable of receiving a rapidmovement of rotation from a suitable motor (not shown), for instancethrough the medium of a transmission comprising a belt, a pulley 2 and ashaft 3.

This turbine rotates about a fixed hollow shaft 4 which passes throughone end thereof, preferably through a hydraulic joint 5 ensuringfluidtightness. r

The shaft contains the inlet and outlet conduits for the products, via:a conduit 6 through which is admitted the mixture to be treated and aconduit 1 through which is admitted the solvent or reagent, a conduit 8through which is discharged the exhausted mixture, and a conduit 9through which is discharged the solvent or reagent loaded with theextracted product. The arrows in full lines indicate the mixture and thearrows in broken lines, the solvent or reagent.

The body I is divided into six juxtaposed compartments C1 C2 C6 by fiveannular partitions N1 N2 N5, and in each of these compartments arearranged two other annular partitions L1 M1, L2 M2 L6 M6, respectively;the partitions M1 to Ms have an outer diameter smaller than the innerdiameter of the body I and the partitions L1 to L6 have a diametersmaller than that of the partitions M1 to Ms. These partitions arearranged as follows:

The partition M1 M6 (each partition bears indicia of the compartment tothe left of which it is located in Fig. 1) is arranged at right anglesto the axis of the turbine, so that a passageway m1 ms is providedbetween its outer edge and the wall of the body I.

To the right of the preceding one, is a partition L1 LG having a centralfrustumshaped portion and the outer edge of which is offset relativelyto that of m1 Me so as to also provide a peripheral passageway 11 ls.

Finally, to the left of each of the partitions M1 M5, is a thirdpartition N1 N5 secured to the inner wall of the body I.

Free narrow spaces D1 De exist between the partitions L, M and othernarrow spaces E1 E5 are provided between the partitions M, N.

The decanting compartments alone are relativedly large.

The circulation of the products takes place moreover through fixedtubes, arranged in the following manner:

The solution is led through compartments C1 Ca from right to left on thedrawing through scoop-pipes f1 f5 one end of which opens in the spacecomprised between the two partitions M, N and having an extensionconstituted by a conduit 02, 0a Os terminating in an annular jet b2 beopening very near the frustum-shaped portion of the corresponding wallL2 Le.

On the other hand, the solvent or reagent flows through the compartmentsCs C1 from left to right on the drawing through scoop-pipes C6, 05, c4,0: which extend from the compartment bearing the same indicia and leadsto the annular jet b bearing a lower indicia.

The inlet ends of the scoop-pipes are so arranged that the liquids entertherein by inertia.

The conduit 6 through which is admitted the solution terminates in aconduit 01 and an annular jet b1 opening in proximity to the wall L1 andto which leads the scoop-pipe C2; the ends of these pipes extend througha relatively important arc of the circumference of the apparatus asdiagrammatically indicated in Fig. 1 The distance separating the fixedand movable surfaces is so adjusted as to ensure satisfactory emulsionof the solution and solvent.

The discharge conduit 9 for the extracted product is fed by a scoop-pipe01 opening in the compartment C1.

The inlet conduit 1 for the solvent or reagent opens in the last annularjet be.

Finally, the discharge conduit 8 for the exhausted solution extendsdown, in the compartment Ce, beyond the last partition L6.

The operation is as follows:

The solution to be treated, admitted through 6 and O1, is projected bythe jet b1 on'the frustumshaped portion of the wall L1, at the same timeas the solvent or reagent which has already passed through the fivecompartments Cc C: and is led to this jet b1 by the scoop-pipe on.

Both liquids, intimately mixed, thus enter the mixing space or chamberD1 in which the exhaustion of the solution begins.

These liquids are subjected to the action of centrifugal force and,owing to their difference of density and of their non-miscibility, theyseparate and form two concentric annular layers P1, P2, the outer layerP1 being formed by the solution, which is the heavier, and the innerlayer P2 by the solvent.

The separating surface X-X of the two layers reaches, during therotation, a level which depends on the radial distance separating theinlet ends of the scoop pipes 01 and f1, cn and la, etc., and on thedensity of the liquids treated, and this radial distance is so adjustedthat in each compartment the said surface of separation X X is locatedat a distance from the axis of rotation at most equal to the radius ofthe respective disc L1 or L2 and however large enough in order that thelayer of solvent comprised between the level X X and the level Y Y ofthe inlet ends of the solvent scoop pipes c1 02 should have a sufficientthickness.

The solvent of the layer P2 is drawn off through the scoop-pipe c1 anddischarged through the conduit 9, whilst the solution, passing throughm1 and E1 is drawn off through the jet f1 and sent, through 02, be intothe compartment 0:.

accesseat the same time as the solvent coming from the compartment C3passes through the scoop-pipe 03.

The exhaustion thus progressively proceeds in the various compartmehtsthrough which pass, on the one hand, the solution and, on the otherhand, the solvent or reagent, according to the counter-currentprinciple.

According to the modification illustrated in Fig. 2 each space D issupplied with a mixture of solvent and solution through a double jethaving two concentric orifices: the inner jet serves for the admissionof the solution, which is sent to it from one compartment by a scooppipe1, and the outer jet serves for the admission of the solvent, which issent to it from the next compartment through a scoop pipe 0.

I claim:

1. An apparatus for removing at least one of the constituents from aliquid mixture by centrifugation of the mixture and scooping theseparate liquid layers, comprising a drum rotatively mounted andlaterally bounded by two annular discs, arranged for forming with thedrum an inner annular compartment, means for causing this drum to rotateat a high speed, two annular discs secured within this drum and arrangedfor dividing said annular compartment into a lateral space of greatwidth, a narrow intermediate space and a narrow lateral space, the disclimiting the narrow lateral space extending outwardly to a smalldistance from the periphery of the drum, and the disc separating theintermediate space from the space of great width extending outwardly toa greater distance from the periphery of said drum, a fixed nozzleopening at the inner periphery of said drum, in the intermediate spaceand directed towards the annular disc separating this space from thespace of greatvwidth, a supply piping opening in this nozzle and adaptedto lead from the exterior the mixture of liquids to be treated, a supplypiping also opening in. this nozzle and adapted to convey the solvent inthe latter, a scoop-pipe extending from the lateral space of great widthand adapted to evacuate the solvent laden with the constituent to beremoved from the mixture, and a scoop-pipe extending from the narrowlateral space and adapted to evacuate the treated and exhausted mixture.

2. An apparatus for removing at least one of the constituents from aliquid mixture as claimed in claim 1, in which the inner peripheralportion of the disc separating the intermediate space from the space ofgreat width, has a portion in the shape of a. conical surface.

3. An apparatus for removing at least one of the constituents from aliquid mixture, as claimed in claim 1, in which the outlet orifice ofsaid nozzle opens against the portion in the shape of a conical surfaceseparating the intermediate space from the space of great width, saidorifice being very close to said conical surface.

4. An apparatus for removing at least one 01 the constituents from aliquid mixture, as claimed in claim 1, in which the end of thescoop-pipe extending from the lateral space of great width and the endof the scoop-pipe extending from the narrow lateral space, are directedin a direction reverse to the direction of rotation of the drum.

5. An apparatus operating on the countercurrent principle for removingat least one of the constituents from a liquid mixture as claimed inclaim It, in which the drum is internally divided into a series ofannular compartments, each of which is divided into a lateral space ofgreat width, a narrow intermediate space and a narrow lateral space, andhas a nozzle within each intermediate space, the piping adapted toconvey the mixture of liquids to be treated opening in the last nozzleat one of the ends of the drum, the piping adapted to convey the solventopening in the last nozzle at the other end of the drum, the narrowlateral space of each compartment being connected to the nozzle of thefollowing compartment, relatively to the direction of circulation of themixture being treated, by a scoop-pipe, and the space of great width ofeach compartment being connected to the nozzle of the followingcompartment, relatively to the direction of circulation of the solvent,by another scoop-pipe.

6. A method for extracting a body from a complex liquid mixture by meansof an auxiliary body acting as solvent or reagent on said body to beextracted, this auxiliary body being liquid and nonmiscible with theliquid mixture to be treated, said method consisting in introducingtogether the liquid mixture to be treated and the auxiliary body into arotary vessel where they come in intimate contact, then separate in theform of concentric layers under the influence of centrifugal force, oneof the layers being especially constituted by the auxiliary body andthat of the liquid bodies it has lved, and the other layer beingespecially cons ituted by the impoverished liquid mixture, and incontinuously extracting from each oi these layers the portion situatednearest the axis of rotation by a scooping operation.

7. A method for extracting a body from a complex liquid mixture by meansof an auxiliary body acting as solvent or reagent on said body to beextracted, this auxiliary body being liquid and nonmiscible with theliquid mixture to be treated, said method consisting in introducingtogether the liquid mixture to be treated and the auxiliary body into arotary vessel where they come in intimate contact, then separate in theform of concentric layers under the influence of centrifugal force, oneof the layers being especially constituted by the auxiliary body andthat of the liquid bodies it has dissolved, and the other layer beingespecially constituted by the impoverished liquid mixture, incontinuously extracting from each of these layers the portion situatednearest the axis of rotation by a scooping operation, and in dischargingthe liquids thus extracted respectively in two other rotary vesselswhere they again separate in the form of concentric layers and so on, sothat the solution circulates in one direction and is consequentlyenriched with the body to be extracted, and the impoverished liq uidmixture insoluble in the auxiliary body circulates in the reversedirection and is consequently purified, the evacuation and transfer ofthe liquids from one vessel to another being always produced by scoopingout from portions of said liquid layers situated the nearest to the axisof rotation.

COUTOR, CHARLES.

